A non progressive model of innovation diffusion in social networks

In this paper we deal with the diffusion of innovation in social network, presenting a non progressive instance of the well known Linear Threshold model. Each individual in the social network is influenced by the behaviour of its neighbours, and at each steps it decides either to adopt, abandon or maintain the innovation by following a threshold mechanism. We assume that the innovation is incepted in the network by a seed set of individuals which are assumed to maintain the innovation independently of the state of their neighbours for a finite time. Here we describe in details the evolution of the system depending on different initial conditions, and in particular we focus on how the system dynamics are influenced by the cohesive sub-groups of the network

On the Spread of Innovation in Social Networks

In this paper we analyse different aspects of the diffusion of innovation in social network. Adopting the linear threshold model we firstly propose an algorithm based on the linear programming which takes as input a set of innovators and returns the maximal cohesive subset contained in the complement of the seed set. Then we introduce and formalize with integer programming two problems. The first one is that of finding a seed set of r individual that maximizes the spread of innovation in the network in k step. The second one is that of finding a seed set whose cardinality is minimal which diffuses the innovation to a desired set of adopters in k steps

Robust common reference estimation and formation control for multi-agent systems

In this paper we propose a decentralized coordination strategy that allows a dynamic multi-agent system to estimate a common reference point and achieve arbitrary spatial formations with respect to the estimated point. The method is robust against measurement noise of odometry or inertial navigation. We assume that the agents are mobile pointmass vehicles that do not have access to absolute positions (GPS)

The Valsalva manoeuvre versus tourniquet for venipuncture

Background: During ultrasound-guided cannulation, venous filling is required for venipuncture. Tourniquet with an elastic tube at the axilla is the most common method to induce venous stasis for cannulation of the deep veins of the arm. Although effective, this method might be associated with short- and long-term complications. Valsalva manoeuvre has been used to produce venous filling in other extrathoracic veins. The aim of this observational study is to demonstrate the effect of Valsalva manoeuvre in respect of the elastic tourniquet on venous distention during echography-guided cannulation of the deep veins of the arm. Method: Sixty-nine patients scheduled for cannulation of basilic or brachial vein were prospectively observed. Vein diameters were recorded at rest and after 10 s of Valsalva or tourniquet placement. Results: The mean difference between basilic vein diameters during tourniquet and Valsalva manoeuvre was 0.006 mm (95% confidence interval = −inf, 0.09) with a standard deviation of 0.5 mm (95% confidence interval = 0.5, 0.7; p &gt; 0.01). The mean difference between brachial vein diameters during tourniquet and Valsalva manoeuvre was 0.04 mm (95% confidence interval = −0.23, 0.15) with a standard deviation of 0.8 mm (95% confidence interval = 0.7, 0.9; p &gt; 0.01). Discussion: This increase in cross-sectional basilic and brachial vein diameters was not different to that obtained with the elastic tube tourniquet. </jats:sec

Environmental indicators in EpiAir2 project: Air quality data for epidemiological surveillance|Indicatori ambientali nello studio EpiAir2: I dati di qualità dell'aria per la sorveglianza epidemiologica

OBJECTIVE: construction of environmental indicators of air pollution suitable for epidemiological surveillance in 25 Italian cities for EpiAir2 project (2006-2010) and presentation of the results from a 10 years of surveillance system (2001-2010) in 10 Italian cities. DESIGN: data on particulate matter (PM10 and its fine fraction PM2.5), nitrogen dioxide (NO2), and ozone (O3), measured in the 2006-2010 calendar period, were collected. Meteorological data needed to estimate unbiased measures of the effect of pollutants are: temperature, relative humidity (estimated "apparent temperature"), and barometric pressure. In continuity with the previous EpiAir project, the same criteria for the selection of monitoring stations were applied and standard methods to estimate daily environmental indicators were used. Furthermore, it was checked the adequacy of the selected data to represent the population exposure. SETTING AND PARTICIPANTS: EpiAir2 project, relativetothe period 2006-2010, involves the cities of Milano, Mestre-Venezia, Torino, Bologna, Firenze, Pisa, Roma, Taranto, Cagliari, and Palermo, already included in the previous study. The city of Treviso, Trieste, Padova, Rovigo, Piacenza, Parma, Ferrara, Reggio Emilia, Modena, Genova, Rimini, Ancona, Bari, Brindisi, and Napoli are added to the previous group. RESULTS: particulate matter concentrations have decreased in most cities during the study period, while concentrations of NO2 and ozone do not show a similar clear trend. The analysis of the trend showed annual mean values of PM10 higher than 40 μg/m3 in some areas of the Po Valley, and annual mean values of NO2 higher than 40 μg/m3 in the cities of Trieste, Milano, Padova, Torino, Modena, Bologna, Roma, and Napoli. CONCLUSION: the enlargement of the EpiAir project to 13 other cities has highlighted critical issues related to the different geographical areas under study. Results of EpiAir2 project point out the need of a monitoring system of air pollution concentrations in both urban and industrial sites, in order to obtain reliable estimates of exposure for resident populations and to evaluate the related time trend

Impatto a breve termine dell'inquinamento dell'aria nelle citt\ue0 coperte dalla sorveglianza epidemiologica EpiAir2

OBIETTIVO: stimare l\u2019impatto a breve termine dell\u2019inquinamento atmosferico sulla popolazione adulta di 23 citt\ue0 italiane nel periodo 2006-2009 nell\u2019ambito del progetto EpiAir2. DISEGNO, MATERIALI E METODI: per ogni citt\ue0 inclusa nello studio \ue8 stato calcolato l\u2019impatto dell\u2019effetto a breve termine dell\u2019inquinamento atmosferico sulla mortalit\ue0. In particolare, sono stati calcolati i decessi attribuibili a concentrazioni delle polveri (PM10 e PM2.5) superiori a soglie differenti definite dalla legislazione europea o nell\u2019ambito delle linee guida dell\u2019Organizzazione mondiale della sanit\ue0 (per il PM10: 20 e 40 \u3bcg/m3, riduzione del 20% ad arrivare a 20 \u3bcg/m3 e superamento del limite di 35 giorni con concentrazioni medie di 50 \u3bcg/m3; per il PM2.5: 10, 18 e 25 \u3bcg/m3, riduzione del 20% ad arrivare a 18 \u3bcg/m3). La stima di impatto \ue8 stata ottenuta combinando la stima di effetto delle polveri, il livello di mortalit\ue0 osservato e i livelli di concentrazione degli inquinanti misurati dalle reti di monitoraggio urbane. Per quanto riguarda le stime di effetto, sono state utilizzate le distribuzioni a posteriori specifiche per citt\ue0 risultanti da una metanalisi bayesiana. L\u2019incertezza sulle stime di impatto \ue8 stata calcolata con metodi Monte Carlo. RISULTATI: nell\u2019insieme delle 23 citt\ue0 valutate nel presente studio il numero di decessi attribuibili agli effetti a breve termine delle concentrazioni di PM10 superiori a 20 \u3bcg/m3 e di PM2.5 superiori a 10 \u3bcg/m3 nel periodo 2006-2009 \ue8 risultato rispettivamente pari allo 0,9% (assumendo indipendenza tra citt\ue0 l\u2019intervallo di credibilit\ue0 all\u201980% \ue8 0,4-1,4) e allo 0,8% (ICr80% 0,2-1,3) della mortalit\ue0 naturale. L\u2019impatto delle concentrazioni di polveri PM10 e PM2.5 \ue8 risultato concentrato nelle citt\ue0 della Pianura Padana, della Piana fiorentina, e nelle grandi realt\ue0 metropolitane di Roma, Napoli e Palermo: per il PM10 la percentuale sui decessi \ue8 risultata 1,0% (ICr80% 0,4-1,5) contro 0,4% (ICr80% 0,2-0,7) nelle altre citt\ue0 analizzate. Se i livelli di concentrazione delle polveri fossero stati inferiori del 20%, complessivamente l\u2019impatto si sarebbe ridotto del 42% per il PM10 e del 51% per il PM2.5. CONCLUSIONI: i livelli di inquinamento osservati nel periodo in studio sono stati responsabili di un numero importante di decessi nelle citt\ue0 analizzate. Politiche di contenimento basate sulla diminuzione percentuale delle concentrazioni annuali di polveri interesserebbero tutte le citt\ue0 coperte dallo studio e potrebbero ridurre in modo importante l\u2019impatto dell\u2019inquinamento sulla salute